Manuel Balce Ceneta/AP

A hunter and lifetime member of the National Rifle Association, Democrat Joe Manchin won his Senate seat after airing an ad that showed him firing a rifle and shooting a hole in the cap-and-trade bill backed by President Obama. Now the West Virginia senator is the point man on Capitol Hill for reviving legislation on background checks for gun buyers that lawmakers killed just three weeks ago. With polls showing the public turning on some Republican senators who voted against the popular bill, Manchin’s crusade for a second wave of gun legislation could succeed.

“This isn’t gun control, this is gun sense,” Manchin said Saturday at a forum in Washington, where he shared the stage with liberal MSNBC host Rachel Maddow. “I’m a gun owner, I come from a gun culture. If I couldn’t bring some credibility to that issue, why am I here?” His goal, he said, is to have another vote in the Senate before the August recess. “We’re going to pass this thing,” he said. “Don’t give up.”

It’s highly unusual after a crushing defeat to ask for a redo and expect that the outcome will be any different in three or four months, but there is reason to take Manchin seriously. Polls taken before the Senate vote showed that more than 90 percent of voters support background checks to keep guns out of the hands of criminals and the mentally ill, and some of those voters have evidently soured on the senators who helped bring the bill down. Conversely, vulnerable Democrats in red states who voted for the bill, like Mary Landrieu in Louisiana and Kay Hagan in North Carolina, are experiencing no ill effects.

“Those who were on the fence and went in the wrong direction are paying a price,” says Jim Kessler with Third Way, a centrist Democratic group. “They seem blind to the voters in their state, and beholden to a special interest.”

Manchin says the bill would have gotten 70 votes in the Senate if the NRA hadn’t “scored” it, meaning a vote for the legislation would have caused a lawmaker’s “score” from the influential gun group to plummet. New Hampshire Republican Kelly Ayotte, the only senator in the northeast to vote against the bill, saw her poll numbers plunge by 15 points. Pennsylvania Republican Pat Toomey, who co-sponsored the bill in a show of independence from both the NRA and the GOP, saw his numbers rise to a record high with 54 percent favoring his work on the compromise legislation and just 12 percent opposing.

A subsequent poll conducted by a Democratic-leaning group, Public Policy Polling, found that five Republicans and one Democrat, Alaska’s Mark Begich, were feeling the heat for opposing the legislation. In addition to Ayotte, the Republicans are Nevada’s Dean Heller, Alaska’s Lisa Murkowski, Ohio’s Rob Portman, and Arizona’s Jeff Flake. All are seen by gun-safety advocates as potential yes votes in a second wave of voting.

“Nothing like waking up to a poll saying you’re the nation’s least popular senator,” Flake wrote on his Facebook page Tuesday. “Given the public’s dim view of Congress in general, that probably puts me somewhere just below pond scum.”

The bill fell six votes short of the 60 needed to avert a filibuster, though one of those votes was cast by Democratic leader Harry Reid who did so on procedural grounds so that he could bring it back under Senate rules. Kessler counts 15 senators who voted no “and are sick to their stomach over it. I’m not going to name them, but their vote comes across as a vote of calculation, not conscience.”

Manchin, an essential ally for Obama as the old politics of guns give way, said the bill will be tweaked to clarify Internet sales and what constitutes a commercial sale versus friends and family–changes that provide political cover for senators to change their vote. “We have got to give them some comfort, you can’t just push ’em and push ’em,” says Manchin, who moves seamlessly across the ideological landscape, schmoozing with Fox News as easily as he does with Maddow.

A former governor, Manchin knows his state and what his constituents are capable of, and he is convinced that given a second chance and a few tweaks he can sell the bill he co-authored with Toomey. Manchin’s tireless promotion of the bill—“Read it,” he implores—is convincing.

Three groups new to the fight will be critical to ramping up the pressure on lawmakers. Mayors Against Illegal Guns cofounded by New York Mayor Bloomberg, Americans for Sustainable Gun Solutions founded by Giffords and Kelly, and the Sandy Hook Promise, the voice and lobbying arm of the Newtown parents. “They’re all start-ups that are gaining influence, members, and money,” says Kessler, who called their very existence evidence that “the old politics might not work anymore on guns.”

“I’ll take the bet this will get to the president’s desk in this session of Congress,” says Kessler, who believes the Senate will pass background checks this year, and then it will take time for pressure to build on the House side next year in the run-up to the midterm elections. “There’s more to go in this fight,” he says. “I like our chances.”